It has long been recognized that young children show deficits, as compared to adults, in the perception of complex visual patterns. A recent experiment conducted by Morton Mendelson and myself has clarified the nature of these limitations by separating the influence of quantitative and organizational pattern variables in a task of paired-comparison judgment of pattern complexity. Children four to seven years of age show a consistent response to increasing pattern quantity (contour) in their judgments, but the structure of patterns is reflected in their judgments only if the amount of contour is low enough. Older subjects respond to the structure of patterns with progressively larger amounts of contour, and older subjects give increasing weight to the structure of patterns. Undoubtedly, these results can be explained in terms of developing capacity for cognitive representation of visual materials, possibly increasing chunk size, increasing memory span, a transition to hierarchical organization of first order chunks, or all of these. The proposed research includes: (1) extension and confirmation of the above findings in an experiment examining the judged complexity of six types of structured patterns; (2) exploration of young children's ability to detect symmetry as a perceptual feature of high contour patterns; and (3) explicit analysis of the subjective organization of patterns as revealed in a pattern copying task in order to confirm the assumption that complexity judgments reflect subjective organization while also revealing the developmental changes in subjective organization that presumably underlie the observed changes in judgment. Analysis of changing subjective organization in this situation should elucidate the nature of changes in general capacities for cognitive representation.